Polymethacrylate viscosity index improvers (PMA VII's) are well known in the lubricating industry. Many attempts have been made to produce PMA VII's that have the desired balance of high temperature and low temperature viscometrics, as well as the required shear stability for a given application. Obtaining suitable low temperature performance has become even more difficult recently with the movement away from API Group I base oils and the increased utilization of Group II and Group III base oils. Further, refiners who blend with different base oils desire a single product which performs effectively in all of these different base oils. The present invention is directed to novel dispersant (meth) acrylate copolymers which exhibit excellent low temperature performance in a wide variety of base oils.
U.S. Pat. No. 5,112,509 teaches a method for making a methyl methacrylate-lauryl methacrylate copolymer. The '509 patent does not teach the copolymers of the present invention, which contain a dispersant monomer.